The French Patent Specification FR-2,410,790 discloses a glass-ceramic cooking unit comprising an electric heating member which is disposed as a helix under the hot plate and also a thermostatic sensor which is thermally coupled to the hot plate within the zone of the cooking surface. The outer zone of the cooking surface is provided with an unheated zone for the thermal coupling of the sensor, the remaining portion of the surface being covered by the two-wire heating member whose connections are located at the periphery of the cooking surface. However a hot plate of such a structure has several disadvantages. Firstly, the heating device is still expensive because of its complex structure. Moreover, it is located at some distance from the glass-ceramic plate, which causes thermal losses. Thus, it is subjected to a cooling and heating time constant which is mainly due to the poor thermal conduction of the air, which renders this type of hot plate less flexible in use than, for example, cookers with controllable flames.